Hi, thank you for contacting JustAnswer.com. My name is Russell. I am interested in providing a good answer to your interesting question.
I have to ask first, though: What organ, by maker and model, are you asking about?
If the sound of bell or bells is built-in to the organ's sounds complement in its memory, then you would have to select that 'sound' or 'sonority', etc.
If it is not built-in, you would have to import it, if it is a relatively modern organ with the capability to import a sound or sonority into its memory.